Well I've been reading through the forum and the rattle noise of the secondary tensioners that tend to fail. Luckily, it seems that these are relatively easy to replace and the part is not very expensive (the metal updated ones.)

I suspect my car have the 2000 plastic ones (53.5 thousand miles.) and given the mileage more than likely there was no reason to upgrade then.

Now, I been having the rattle on cold starts (first thing in the morning usually or about 4-5 hours of sitting) that last about 1 to nearly 2 seconds or about 4-5 rattles (never made it to two by manual count and by clock). Some say the VVT can produce the noise on cold start up too. After the rattle subsides, there is no noise at all that is noticable from the timing chain area and car runs smooth as normal and for subsequent start ups even ones if car is immediately shut off and restarted.

My first guess given the research is the secondary timing tensioners (which I was going to order this month anyways to upgrade to the metal just cause before my cross country trip).

While I wait for the parts, I'm wondering what exactly causes the rattling noise, assuming it is the tensioners. Could it be that the tensioner is spring loaded and depend on oil pressure to make adjustments and given that most of the oil have settled back into the pan by the time 4 or more hours have passed and that second is the oil getting back to the tensioner, thus rattle. Or something is loose, which would lead me to believe that the rattle would be present even at idle or subsequent start ups (had a Merc. that had loose tensioner (luckily it truned out to be a bolt that was improperly torqued that came loose and luckily we found it in time before it was totally dislocated and possible getting caught in the timing workings.) and it would rattle in any case cold or warm. I understand the secondary tensioners have plastic "slippers" that come in contact with the chain if one goes missing it would be metal to metal and may or may not make noise due ot the oil but in either case will wear down the chain quicker.

Now if it's the VVT thing that rattles, what in world causes that thing to rattle? I was under the impression it was merely a cpu like electronic device hooked up to the spocket. And while we on the subject of VVT, what exactly do it do and given that the XJR has the same engine with supercharger sans VVT, is this thing actually a needed component. And what would the effects be if say one would theorectically threw in a normal XJR spocket and got rid of the VVT?

And lastly when the secondary tensioners come in, how easy is it to replace them? There is only one "Jag dealership" here which is combined with Subaru and Audi and no different than a glorified overpriced independent shop and notorious here for customers having to return for repeated work aka shabby work. I have a trusted independent mechanic that do this timing chain work often and ironically his computer was only able to quote me for the primary chain tensioners and guides ($550 labor) and said that the secondary tensioners are included in that price.
Although I have a warrenty on the car, it only covers things like this if it fails and not preventive (which would cause engine destruction from my understanding and I dont understand why they would rather pay up to 10,000 on a repair instead of a $1,000 or so prior as my deductable is only $100 either way.). Basically in order for it to be warrenty repair I have to continue on until they actually break. go figure.

 

Hi,
i stripped my xjr down to check tensioners and was surprised to see later type metal tensioners ,but i found alot of slack in in the chains,Have since ordered new secondary chains with split link and new tensioners again.

I would advise you to remove a cam cover and have a look.

Kev

 

I think I shall. Looks like it can be done in a couple of hours on a nice week end day. Just hope this blasted wind dont kick up a lot of dust just as I'm opening it up.